Study on physicochemical properties of U3+ in LiCl–KCl eutectic media at 773 K

In order to enhance the efficiency of pyrochemical technology, especially electrorefining process, physicochemical data of trivalent uranium in LiCl–KCl eutectic at 773 K were measured, including molar absorptivity, formal potential and diffusion coefficient of U 3+ ions. The molar absorptivities of U 3+ were determined to be 765 ± 48 and 686 ± 39 M −1 cm −1 at 465 and 550 nm, respectively. The formal potential of U 3+ /U 4+ redox couple and diffusion coefficient of U 3+ ions were measured to be −0.308 V vs. Ag/Ag + and 8.7 × 10 −6 M −1 cm −1 , respectively. To elucidate the chemical behavior of U 3+ ions under the existence of oxide ions, U 3+ ions were reacted with oxides ions in situ produced at the LiCl–KCl media. Surprisingly, it was revealed from XRD patterns that UO 2 was formed from the reaction between U 3+ ions and O 2− ions with the molar ratio of 1:1.